Reed block crankcase induction for two-cycle engine

ABSTRACT

A V-type reed block extends circumferentially of the crankcase in excess of 60* and is curved to conserve space requirements within the crankcase chamber.

United States Patent [72] Inventor Elmer Carl Kiekhaefer [56] References Cited Winter Haven, UNITED STATES PATENTS I211 P 331 a 2,639,699 5/1953 Kiekhaefer 123/73 I d J 2,669,979 2/1954 Kiekhaefer..... 123/73 3; 2*; Co ration 2,706,972 4/1955 Kiekhaefer 123/73 1 ,m FOREIGN PATENTS acorporationof Delaware 887,051 1/1962 Great Britain 123/73 1 Primary Examiner-Wendell Burns 54 REED BLOCK CRANKCASE INDUCTION FOR W 5 99197 7 TWO-CYCLE ENGINE 9 Claims, 4 Drawing Figs.

U.S. C|.... 123/73 F021) 33/04 ABSTRACT: A V-type reed block extends circumferentially Field of Search 123/73V, of the crankcase in excess of 60 and is curved to conserve 73Dl, 73D, 73 space requirements within the crankcase chamber.

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Attorneys PATENIEU JAN 1 2 Ian SHEET 2 OF 2 INVENTOR. ELMER c. KIEKHAEFER Attorneys REED BLOCK CRANKCASE INDUCTION FOR TWO- U CYCLE ENGINE ACK ROU D 7' Reed blocks have been variously-located relative to the crankcase and cylinder and in'nearly'allj instances the block has been of limited length to avoid enlarging the crankcase chamber and thereby lessening of crankcasecompression.

, SU ARY w According to the present invention the V type reed block is curved generally corresponding to the curvature of the crankcase'opposite the cylinder and is constructed to provide a series Y of reed-controlled valve openings on each side of the block. F

The construction provides a substantially greater total area of reed valve openingthan previously possible. At the same time, the construction keeps thecapacity or volume of the crankcaseata minimum so that the desired crankcase compression is obtained. I

v DRAWINGS. Q

The best mode contemplated for carrying out the invention is illustrated in the accompanying drawings in which: I

FIG. 1 is a sectional view of a crankcase for a two-cycle twocylinder engine taken axially of the. crankcase and with parts in elevation; 1

F IG, Zis a' sectional view parts in elevation;

FIG. 3 is an. enlarged view of a portion of FIG. 1 with the taken'on line 292 or'rio. lwith reeds flexed; and

FIG. 4 is a view similar to FIG.2 showing a modified construction. a i Y r l f BRIEF- DESCRIPTION The crankcase illustrated is composed of two halves 1 and 2 flanged and bolted together along a central plane. Crankcase member 1 has a flange 3 to which the'separate cylinders 4 and 5 are secured. a

The crankcase members 1 and 2 cooperate to provide a crank chamber 6 for each cylinder, with end walls having suitable bearings inwhich the crankshaft 7 rotates.

The crankshaft 7- has a crank throw 8 and a counterweight 9 in each chamber 6, and a connecting rod 10 connects the throw 8 to thepiston 11 in the corresponding cylinder.

Each crank-chamber (Sis generally just large enough to ac- 'commodate the-rotation of the corresponding crank 7, throw 8 and counterweight 9. 1

In carrying out the present invention for the'e'mbodiment of FIGS. 1 and 2 the lower crankcase member 2 has a semicircular recess which may be tenned the induction chamber l2-and I which receives a semicircular Y-t'ype reed block 13 for controlling the induction of gases to each crank chamber 6 for operation of the engine.

fuel-oil mixture into the crank chamber 6.

The fuel-oil mixture generally referredito as gases is supplied ,to the block 13 by thepassage I6 from carburetor l7 and which connects throughthe'wall of member 2 to the hollow art of block 13.

T e openings 15 are normally'closed'by individual reeds I8 secured by screws 19 to the corresponding sidewalls of block gases into the chamber 6 from thecarburetor 17.

The reeds 18 are arranged radially of the crankshaft 7 and are secured at their outer ends so that flexing of the reeds results in uncovering the correspondingopening adjacent the apex, and the reed generally directs the gases toward the space between the crank arms and their counterweights, as shown in FIG. 3. v

By reason of the large number of openings possible with the construction illustrated the amount of flexing for each reed may be reduced and the space forthe induction chamber 12 may be kept at a minimum.

FIG. 4 illustrates a modification where the reed block 20 extends approximately 60of the crank chamber instead of approximately l80as in FIGS. 1 and 2.

In this FIG. 4 construction the crankcase member 21, corresponding to member 2 of the first embodiment, has a slot in its outer wall and which is closed by the V-block 20.

The inlet passage 22 isin communication with the block 20 and connects the same to the carburetor, not shown. The reed crankshaft axis, the sidewalls of said block being angularly disposed to present an apex directed toward the crankshaft,

said reed block having a series of circumferentially spaced 1 openings in each sidewall thereof and corresponding individual reeds over each opening for controlling the induction of gases through said openings into the crankcase from said passage.

2. The construction of claim 1 wherein each said reed is secured to said block at the end farthest from the crankshaft axis.

3. The construction of claim 1 in which said reed block closes a slot in the back side of the crankcase.

4. The construction of claim 1 in which said reed block ex crank casing with ing with the reeds extending radially of the crankshaft.

5. The construction of claim 4 wherein each said reed is secured to said block at the end farthest from the crankshaft axis. e

6. The construction of claim 4 in' which said reed block I closes a slot in the back side of the crankcase.

- 7. The construction of claim I in which said reed block ex. tends forapproximately land is disposed in a recess in the the reeds extending radially of the crankshaft.

closes a slot in the back side of the crankcase. 

1. In a two-cycle engine having a crankshaft, a crankcase and an induction passage, the improvement comprising a curved V-shaped reed block extending on a radius from the crankshaft axis, the sidewalls of said block being angularly disposed to present an apex directed toward the crankshaft, said reed block having a series of circumferentially spaced openings in each sidewall thereof and corresponding individual reeds over each opening for controlling the induction of gases through said openings into the crankcase from said passage.
 2. The construction of claim 1 wherein each said reed is secured to said block at the end farthest from the crankshaft axis.
 3. The construction of claim 1 in which said reed block closes a slot in the back side of the crankcase.
 4. The construction of claim 1 in which said reed block extends for at least 60* and is disposed in recess in the crank casing with the reeds extending radially of the crankshaft.
 5. The construction of claim 4 wherein each said reed is secured to said block at the end farthest from the crankshaft axis.
 6. The construction of claim 4 in which said reed block closes a slot in the back side of the crankcase.
 7. The construction of claim 1 in which said reed block extends for approximately 180*and is disposed in a recess in the crank casing with the reeds extending radially of the crankshaft.
 8. The construction of claim 7 wherein each said reed is secured to said block at the end farthest from the crankshaft axis.
 9. The construction of claim 7 in which said reed block closes a slot in the back side of the crankcase. 